diff -up bitops/bitops/src/bit-ops.c.armfix bitops/bitops/src/bit-ops.c
--- bitops/bitops/src/bit-ops.c.armfix	2013-08-16 09:54:59.216088912 -0400
+++ bitops/bitops/src/bit-ops.c	2013-08-16 09:55:23.444089276 -0400
@@ -29,7 +29,7 @@ SEXP bitFlip(SEXP a, SEXP bitWidth ) {
 		if ( !R_FINITE(xa[i]) || logb(xa[i])>31 ) xaflip[i]=NA_REAL ;
 
 		else {
-			tmp=(unsigned int) xa[i] ;
+			tmp=xa[i] < 0 ? (int) xa[i] : (unsigned) xa[i];
 			xaflip[i]=(double) ( ~tmp & mask ) ; 
 		}
 	}